docs/bevy/examples/picking/sprite_picking.rs 5.8 K · 162 lines · raw · history

1 //! Demonstrates picking for sprites and sprite atlases.
2 //! By default, the sprite picking backend considers a sprite only when a pointer is over an opaque pixel.
3
4 use bevy::{prelude::*, sprite::Anchor};
5 use std::fmt::Debug;
6
7 fn main() {
8 App::new()
9 .add_plugins(DefaultPlugins.set(ImagePlugin::default_nearest()))
10 .add_systems(Startup, (setup, setup_atlas))
11 .add_systems(Update, (move_sprite, animate_sprite))
12 .run();
13 }
14
15 fn move_sprite(
16 time: Res<Time>,
17 mut sprite: Query<&mut Transform, (Without<Sprite>, With<Children>)>,
18 ) {
19 let t = time.elapsed_secs() * 0.1;
20 for mut transform in &mut sprite {
21 let new = Vec2 {
22 x: 50.0 * ops::sin(t),
23 y: 50.0 * ops::sin(t * 2.0),
24 };
25 transform.translation.x = new.x;
26 transform.translation.y = new.y;
27 }
28 }
29
30 /// Set up a scene that tests all sprite anchor types.
31 fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
32 commands.spawn(Camera2d);
33
34 let len = 128.0;
35 let sprite_size = Vec2::splat(len / 2.0);
36
37 commands
38 .spawn((Transform::default(), Visibility::default()))
39 .with_children(|commands| {
40 for (anchor_index, anchor) in [
41 Anchor::TOP_LEFT,
42 Anchor::TOP_CENTER,
43 Anchor::TOP_RIGHT,
44 Anchor::CENTER_LEFT,
45 Anchor::CENTER,
46 Anchor::CENTER_RIGHT,
47 Anchor::BOTTOM_LEFT,
48 Anchor::BOTTOM_CENTER,
49 Anchor::BOTTOM_RIGHT,
50 ]
51 .iter()
52 .enumerate()
53 {
54 let i = (anchor_index % 3) as f32;
55 let j = (anchor_index / 3) as f32;
56
57 // Spawn black square behind sprite to show anchor point
58 commands
59 .spawn((
60 Sprite::from_color(Color::BLACK, sprite_size),
61 Transform::from_xyz(i * len - len, j * len - len, -1.0),
62 Pickable::default(),
63 ))
64 .observe(recolor_on::<PointerOver>(Color::srgb(0.0, 1.0, 1.0)))
65 .observe(recolor_on::<PointerOut>(Color::BLACK))
66 .observe(recolor_on::<PointerPress>(Color::srgb(1.0, 1.0, 0.0)))
67 .observe(recolor_on::<PointerRelease>(Color::srgb(0.0, 1.0, 1.0)));
68
69 commands
70 .spawn((
71 Sprite {
72 image: asset_server.load("branding/bevy_bird_dark.png"),
73 custom_size: Some(sprite_size),
74 color: Color::srgb(1.0, 0.0, 0.0),
75 ..default()
76 },
77 anchor.to_owned(),
78 // 3x3 grid of anchor examples by changing transform
79 Transform::from_xyz(i * len - len, j * len - len, 0.0)
80 .with_scale(Vec3::splat(1.0 + (i - 1.0) * 0.2))
81 .with_rotation(Quat::from_rotation_z((j - 1.0) * 0.2)),
82 Pickable::default(),
83 ))
84 .observe(recolor_on::<PointerOver>(Color::srgb(0.0, 1.0, 0.0)))
85 .observe(recolor_on::<PointerOut>(Color::srgb(1.0, 0.0, 0.0)))
86 .observe(recolor_on::<PointerPress>(Color::srgb(0.0, 0.0, 1.0)))
87 .observe(recolor_on::<PointerRelease>(Color::srgb(0.0, 1.0, 0.0)));
88 }
89 });
90 }
91
92 #[derive(Component)]
93 struct AnimationIndices {
94 first: usize,
95 last: usize,
96 }
97
98 #[derive(Component, Deref, DerefMut)]
99 struct AnimationTimer(Timer);
100
101 fn animate_sprite(
102 time: Res<Time>,
103 mut query: Query<(&AnimationIndices, &mut AnimationTimer, &mut Sprite)>,
104 ) {
105 for (indices, mut timer, mut sprite) in &mut query {
106 let Some(texture_atlas) = &mut sprite.texture_atlas else {
107 continue;
108 };
109
110 timer.tick(time.delta());
111
112 if timer.just_finished() {
113 texture_atlas.index = if texture_atlas.index == indices.last {
114 indices.first
115 } else {
116 texture_atlas.index + 1
117 };
118 }
119 }
120 }
121
122 fn setup_atlas(
123 mut commands: Commands,
124 asset_server: Res<AssetServer>,
125 mut texture_atlas_layouts: ResMut<Assets<TextureAtlasLayout>>,
126 ) {
127 let texture_handle = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");
128 let layout = TextureAtlasLayout::from_grid(UVec2::new(24, 24), 7, 1, None, None);
129 let texture_atlas_layout_handle = texture_atlas_layouts.add(layout);
130 // Use only the subset of sprites in the sheet that make up the run animation
131 let animation_indices = AnimationIndices { first: 1, last: 6 };
132 commands
133 .spawn((
134 Sprite::from_atlas_image(
135 texture_handle,
136 TextureAtlas {
137 layout: texture_atlas_layout_handle,
138 index: animation_indices.first,
139 },
140 ),
141 Transform::from_xyz(300.0, 0.0, 0.0).with_scale(Vec3::splat(6.0)),
142 animation_indices,
143 AnimationTimer(Timer::from_seconds(0.1, TimerMode::Repeating)),
144 Pickable::default(),
145 ))
146 .observe(recolor_on::<PointerOver>(Color::srgb(0.0, 1.0, 1.0)))
147 .observe(recolor_on::<PointerOut>(Color::srgb(1.0, 1.0, 1.0)))
148 .observe(recolor_on::<PointerPress>(Color::srgb(1.0, 1.0, 0.0)))
149 .observe(recolor_on::<PointerRelease>(Color::srgb(0.0, 1.0, 1.0)));
150 }
151
152 // An observer that changes the target entity's color.
153 fn recolor_on<E: EntityEvent + Debug + Clone + Reflect>(
154 color: Color,
155 ) -> impl Fn(On<E>, Query<&mut Sprite>) {
156 move |ev, mut sprites| {
157 let Ok(mut sprite) = sprites.get_mut(ev.event_target()) else {
158 return;
159 };
160 sprite.color = color;
161 }
162 }